Title: How much life has ever existed on Earth?
Time: 10:30am
Where: GSC Ottawa, 601 Booth Street, Room 250; virtual via Teams
Virtual Format (Teams)
Meeting ID: 233 681 487 249
Passcode: DuDCp5
Abstract: The rate of primary productivity is a keystone variable in driving biogeochemical cycles today and throughout Earth’s past. For example, it plays a critical role in determining nutrient stoichiometry in the oceans, the amount of global biomass and the composition of Earth’s atmosphere. Modern estimates suggest that terrestrial and marine realms contribute near-equal amounts to global gross primary productivity (GPP). However, this productivity balance has shifted significantly in both recent times and through deep time. Combining the marine and terrestrial components, modern GPP fixes ≈250 billion tonnes of carbon per year. A grand challenge in the study of the history of life on Earth has been to constrain the trajectory that connects present-day productivity to the origin of life. In this talk I will address this gap by piecing together estimates of primary productivity from the origin of life to the present day. I will then project these results to try to get at some fundamental aspects of Earth's biosphere such as how many cells have occupied the Earth to date? How much carbon has the biosphere ever fixed? And what is the most numerous group of organisms to have ever existed?
Speaker Bio: Peter Crockford is an Assistant Professor at Carleton University in the Department of Earth Sciences. His research primarily focuses on Precambrian Earth history where he and his group utilize a wide range of geochemical tools to build and understand proxies applied to the sedimentary record. He Obtained his Ph.D. from McGill University where he focused on multiple sulfur and triple oxygen isotope geochemistry of Precambrian sulfate minerals. At the moment his interests are focused on understanding the fidelity of carbonate records and to what degree much of the variability in this archive is a consequence of sampling a diversity of environments.